Abstract

Question

Data sources

English-language studies were identified by searching MEDLINE (1966 to 1996) with
the terms decontamination, prophylaxis, intensive care units, and antibiotics. Recent
meta-analyses were reviewed, and investigators involved in primary studies were contacted.

Study selection

Studies were selected if they were prospective, randomized, or time series studies
evaluating the efficacy of SDD. Studies using historic controls were considered for
patient populations for which available evidence was limited.

Data extraction

Data were extracted on randomization, blinding, analysis, patient selection, similarity
of groups at baseline, extent of follow-up, treatment protocol, co-interventions,
and number of patients who received an intervention other than that to which they
were allocated. Outcomes of interest were death, nosocomial infections (pneumonia,
bacteremia, urinary tract infection, and wound infection), and length of intensive
care unit (ICU) stay.

Commentary

SDD is a strategy aimed at reducing the contribution of gut flora to infectious complications
in patients who are seriously ill. Randomized trials and several meta-analyses have
clearly shown that SDD decreases the incidence of pneumonia. Although few individual
trials have shown an effect on survival, the most recent meta-analysis by the SDD
Trialists Collaborative Group showed a clinically important and statistically significant
reduction in mortality (1).

Surgical ICU patients treated with SDD had a 30% lower mortality risk than control
patients, whereas medical ICU patients derived no such benefit. The apparent beneficial
effect of SDD in surgical ICU patients may reflect a higher risk for as-piration pneumonia
related to anesthesia, surgical manipulation, trauma, or prolonged gut dysfunction.
Given the 30% attributable mortality rate of pneumonia in ICU patients (2), an effective pneumonia prevention strategy may confer some mortality advantage.

This meta-analysis should stimulate a reexamination of SDD in selected patient groups.
Uncertainty exists about which surgical patients are most likely to benefit, the long-term
emergence of resistant organisms, conflicts with current prophylactic and perioperative
antibiotic regimens, and unevaluated costs. The results provide justification for
large trials of SDD incorporating systemic-only treatment arms and microbiologic surveillance
in well-defined surgical patient subsets, particularly those at high risk for pneumonia.